Chemists begin building database of dust particles

Chemists from Ohio State University made an accidental
discovery when testing out a new infrared sensor. Some dust got
stuck inside the device's metal mesh, and the team discovered they
could measure the composition of individual dust particles.

Before long, the team -- headed up by chemistry professor James
Coe -- had catalogued 63 unique dust particles from the air in
their laboratory -- and that's just the beginning. Coe and
colleagues now aim to build a comprehensive library of all dust particles.

The first batch of dust contains particles, as revealed by Coe,
from a mix of organic, mineral and man-made sources. 40 of the
particles were organic in nature, emanating from plant or animal
material -- though finding their exact -- icky -- origin, will
require further testing.

The second most prolific ingredient was the mineral quartz,
which was found in 34 of the samples. Man-made chemicals from air
pollution, fertilisers, and construction materials were also
present in small amounts. "A single dust particle is like a
snapshot of mankind's impact on the environment," Coe
said.

The sensor that Coe's team was testing has a fine metal mesh,
and the device transmits infrared light through materials caught in
the holes. It's ideal for picking up the composition of single dust
grains, and, "we can separate particles by size to isolate the ones
that are small enough to get into people's lungs, and look at them
in detail," said Coe.

A library of dust types could aid the study of respiratory
diseases that are caused by airborne particles. A lung disease
called silicosis,
Coe explains in an example, was caused by silica dust from mining
operations.